Artificial limb



.Mafch 29, 1949. R. H. WEAVER 2,465,771

ARTIFICIAL LIME I Filed Dec, 8' 1945 sf/f/f" Fm m Bij/K7 A TORNEY Patented Mar. 29, 1949 UNITED STATES. PATENT OFFICE ARTIFICIAL LIMB Ralph H. Weaver, Fayetteville, Ark.

Application December 8, 1945, Serial No. 633,649

2' Claims. l

My present invention relates to an improvement inarticial limbs, and has for an object the provision of an artificial leg embodying an improved locking means for the knee joint which comprises a single, gravity actuated member associated with the upper and lower portions vof the leg, and which may be readily disengaged by the wearer to permit full bending of the knee.

Another object of my invention is to provide an artificial leg, which, in association with the above enumerated feature, comprises a foot portion pivotally secured to the lower leg and having associated therewith a spring adapted to bias the foot portion toward the normal or rest'` position.

A further object is to provide an artificialV leg in which the toe section is hingedto the foot, and in which a spring associated with the foot and toe portions biases the toe to rest position.

Further objects are to provide an artificial leg which is simple of construction, light in weight and yet strong enough to withstand the strains imposed by walking, and to arrange the knee and spring biased ankle and foot joints so that the functioning of the leg corresponds as nearly as possible to the action of the natural limb.

The above and other features of my invention are illustrated in the accompanying drawing,V forming a part of this application, in which Fig. 1 is an elevational view of my improved articial leg;

Fig. 2 is a sectional view taken through the knee joint and illustrating the locking means therefor;

Fig. 3 is a detail view of the knee joint drawn toa somewhat smaller scale than Fig. 2 and showing the leg in full bended position; and` Fig. 4 is a detail sectional view through the ankle and foot portions of the leg.

Referring now to the drawing for a better understanding of my invention, my improved artie cial leg' comprises an upper portion II, a'lower portion I2, both o which may be partially hollow for the sake of lightness, and a foot portion indicated generally by the numeral I3. The. upper portion I I ispivotally secured to the lower portion I2 to form a knee joint I4 by means of a plate I6, made fast on the lower portion I2 by pins I5; and a pivot pin I1 which passes through the plate and leg portion I2. It will be noted that the hinge arrangement thus formed is located toward the rear side of the leg leaving space toward the front to accommodate the lock mechanism now to be described.

Referring now more particularly to Figs. 2 and 3 of the drawing, it will be seen that the lower end of the upper portion II is hollow with a solid end portion 20 having hole I8 extending therethrough within which is slid-ably mounted a pin I9; The lowerend 2l of the pin I9 projects from the upper leg portion Ii into a recess 22 provided in the top of the lower leg portion l2. It will be noted that the recess 22 is elongated from front to rearl of the leg thus permitting the lower leg `portion to have a limited pivotal movement when the pin is in its lowerrnost. position as indicated in Fig. 2. Therefore, when walking, the lower leg portion l2 is free to bend backward about the pin II, the extent ci this bending action being limited by the pin striking the front wall 24 of slot 22. The front wall 24 is inclined rearwardly of the leg so that as the upper portion II: pivots, the' lower end 2I of pin i9 lies dat against the wall, thus aording a better bearing contact.

Aty its upper end, pin I9 is provided with a head 26 which limits its downward movement in the hole i8; The head is adapted to receive a flexible member 2l, such for instance as a strong cord, which passes through the upper leg portions- II and emerges as at 2S, thence upward beneath the trouser leg where its end may be secured to any suitable portion of the wearers clothing.

When the wearer desires to sit down he pulls upwardly on.` member 21, thus raising the pin I9 and its lower end. 2l from the slot 22, whereupon the knee joint is 'unlocked and the leg is free to bend substantiallyk asy shown in Fig. 3. It will bez noted that thev pin I9 is gravity actuated and that no springs or other devicesr are employed to cause it to. enter or be disengaged from the slot 22. Therefore,l when the wearer desires to lock the joint he stands up, straightening the leg, and pin IQ drops' by gravity' into the recess 22.

In order-tc prevent the accumulation of foreign matter within the. ioint'and to round off the knee jointfwhen the ,leg is. bent, I. provide a. exible shieldZ'Sftherefor, which may be: made of rubber or'otherl elastic materialyand lwhich is secured along its upper edge 3l and lower edge 32 to the respective upper and lower leg portions il and I2. When the leg is bent as shown in Fig. 3, the front portion 33 of the shield 29 stretches, whereas the rear portion thereof is compressed as indicated by the folds 34, Fig. 3.

Referring now to Fig. 4 of the drawing, the lower portion of the leg embodies the foot I3 pivotally secured to the lower leg I2 as at 36 to form an ankle joint 31. The lower end of the leg portion I2 is provided with a recess 38 adapted to receive a spring 39 having one end thereof secured to a lug 4I on the leg portion I2, and the other` end secured to a lug 42 fast to the foot I3. The spring is under tension so that the foot I3 is biased always to the rest position, yet is free to bend as does the human foot when the user is walking.

The under portion 43 of the foot I3 is provided with a recess 44 within which is placed a spring 46, having one end thereof secured to a lug 4'1 fastened to the foot, and its other end secured to a lug 48. The lug 48 is secured to a toe portion 49 which is hinged to the body of the foot I3 by a hinge 50. The spring 46 is under tension so that the toe 49 is biased to the restposition.

From the above the operation of my improved articial leg will be readily understood. The leg is strapped to the wearers body, by any suitable means, not shown, and with the upper end of the flexible member 2'I secured to a suitable portion of his clothing so that it may be pulled to actuate the pin I9. In normal walking position the lower end 2l of pin I9 is resting within the recess 22 so that the knee joint is free to bend as shown in the dotted lines, Fig. 2. When the wearer desires to sit down, he pulls upwardly on member 2l, raising the pin I9 and removing its lower end from the recess 22. As shown in Fig. 3, it will be apparent that the leg portion I I is then free to bend backwardly with respect to the lower leg portion I2. Upon arising, and when the leg is straightened, the pin I9 drops by gravity into recess 22, thus automatically locking the joint in the walking position.

As the lower leg portion I2 pivots about the ankle joint 3'1, the springs 39 and 46 tend to return both the foot and toe portions to rest position. However, the tension on the springs is insuicient to hinder free and comfortable action of either of the joints, but is suilicient to return both the joints to the rest position, thus electively eliminating the undesirable feature of having these portions of the leg loosely hinged.

In actual practice, I have found that an artificial leg made in accordance with my invention is both simple of construction and comfortable to wear. Further, since the llexible member 21 may extend to the upper portion of the wearers body beneath the trouser leg, I have found that it is most convenient and presents no unsightly appearance as its upper end may be fastened to a part of the under clothing or carried over the shoulder. A knee joint constructed in accordance with my invention is positive of operation, and the spring biased lower foot portions give added walking stability to the wearer.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In an artificial leg, an upper portion, a lower portion, hinge means for joining said portions together and disposed toward the rear of the leg, a vertically disposed slot in the lower end of the upper portion, a gravity actuated pin slidably disposed in the slot and projecting from the upper portion, ahead on the pin to limit its downward movement within said slot, a recess in the upper end of the lower leg portion elongated from front to rear of the leg and within which the lower end of said pin fits to permit limited pivotal action between the upper and lower leg portions, a flexible member connected to the head of said pin and extending upwardly through the leg and accessible to the wearer thereof to disengage the pin from said recess, a foot pivotally connected to the lower leg portion, a spring disposed internally of the lower portion and associated with the foot to bias it to rest position, a toe section hinged to the top of the foot section, and a spring disposed internally of the foot and associated with the toe portion to bias it to rest position.

2. In an artiiicial leg, upper, lower and foot portions pivotally connected to form knee and ankle joints, the pivot between said upper and lower portions being disposed toward the rear side of the knee joint, there being a vertically disposed slot through the lower end of the upper portion located toward the front side of the knee joint, a gravity actuated pin slidably disposed in said slot with one end projecting into said lower portion, there being a recess in the lower portion for receiving the projecting end of said pin, said recess being elongated from front to rear of the knee joint, a rearwardly inclined wall forming the front of said recess against which the projecting portion of said pin is adapted to strike thus to limit bending action of the knee joint, a head on the opposite end of said pin, a flexible member connected to the head extending externally of the leg and accessible to the wearer thereof to withdraw said pin from said recess, a coil spring longitudinally disposed within the connes of the lower leg portion adjacent the ankle joint and connected to the foot to bias it toward rest position, a toe section hinged to the top of the foot, and a coil spring longitudinally disposed within the confines of the foot to bias the toe section toward rest position.

RALPH H. WEAVER.

REFERENCES CITED The following references are of record in the file of this patent:

'UN'.[TED STATES PATENTS Number Name Date 1,343,298 Worman June 15, 1920 2,127,566 Malloy-Brehumoff Aug. 23, 1938 FOREIGN PATENTS Number Country Date 35,808 Germany June 12, 1886` 

